\section{Evaluation Result}\label{sec_evaluation}


\subsection{Discussion}\label{subsec_discussion}
It was clear that the system required a more thorough introduction to the mechanisms of the KAPTCHA

A common statement made in the 
\begin{quote} Once it became clear what they were suppose to do, the system was very easy to use.\end{quote}


As a result of this evaluation one significant change was made to the image labeller game.  The introduction of a 
It should be noted that this evaluation was conducted during a time when some (both level three and four) of the participants were extremely busy with an assessed exercise.  This however was the only time available for the completion of this task.  The evaluation would have preferably been completed when the majority of the participants had more time to spend playing the game.  


This was reflected in the initial timing results created for the system.  The first attempts for almost all of the participants was significantly larger than that of subsequent attempts.  The participants in the study were all proficient in the use of the computers, people who have recently lost their eye sight and are adjusting to using computers are likely to have significantly more problems.


I believe that the system is not secure enough in its current configuration this was demonstrated by the relative ease in which the attack broke the CAPTCHA, the addition of the labels which allow screen readers to make the association between the matching term and the image, presents too big a security hole.  The removal of these labels and with significantly more labelled images than the number used in the study would provide a highly effective CAPTCHA.

KAPTCHAs are a significant step in the field of usability as they challenge the one of the biggest usability problems which blind users face.

I would be important that the level of security provided by any highly accessible is , as security is only as good as its weakest point\cite{weaksecurity}

This breaks the nature of what a CAPTCHA is suppose to be, a system based on the use of people and would require the 

This exploits the explosion of Web2.0 and gaming which was not prevalent in 2000 when the term CAPTCHA was coined.  That until artificial intelligence programs can interpret and label an image that the use of humans to generate generate CAPTCHA 


I believe that the game requires the addition of stemming. Stemming reduces a word to its root, this would reduce the number of labels which could be added to the 

this would increase the accuracy of the system as it would protect against users, although this would increase the accuracy of the labelling game it would present the problem of transforming the stemmed words to their <FULL version> for the CAPTCHA game.

If the problems which currently affect KAPTCHAs are solved then this would be a significant milestone in providing a highly accessible to all people irrespective of the users visual status.
